Signal receiving system



July 9, 1935.

W. R. KOCH v SIGNAL RECEIVING SYSTEM Filed Aug. 19, 1950 hun \w mu. n n mw I i J l uw l E mm I g I I I I ...m I mm m um I. I II a. I In@ @Imm Mm, w mm. V N j l `N mw# I I T l W I T. .H H @lm w DTII o., n

N UNITED STATE V August 15,v

0` its method of operation,

Patented `Iuly 9, 1935 SIGNAL REGE Winnen Rudolph Koch, by mesne assignments,

America, New York, Delaware means for automatic volume control are-included. `When an attempt is madeto tune a radio receivingsystem of the type including automaticv volume controlrmean's,. some. difficulty is experienced in obtaining..exacttuning The difficulty is accentuated when the system isremotely coni trolled and. it is particularly apparent when the receiving system is basedv uponthe super-heterodyneprinciple. .Y

It is accordingly an'` object of my invention to provide means for visually. indicating the tuning of a radio receiving systemito exact resonance with an incoming signal. i

Another object of my. invention is to. provide visual indicating means that shall beenergized only during the reception of` a signal from a desired transmitting station;Y v

Another object of my invention is to provide, in a radio receiving system of the type comprising visual indicating means, instrumentalities whereby the said indicating meansshall be deenergized during the tuning operation.

A still further and more specific object ofmy invention is to provide, in a radio receiving system of the type disclosed in the co-pending applicationl of G. L.- Beers, Serial No. 475,474 iiledAugust i930, and assigned to RCA Victor Company, Inc., lmeans wherebythe actuation of a background-suppressor device shallalso de-energize a visual indicating device. t

The foregoing objects and others appurtenant thereto that, hereinafter, will become apparent, I prefer to accomplish through the vmedium of arelay devicethat is serially included in the plate or output circuit of an amplifier tube. i,

VThe relay device is provided with a front and a back contactthat cooperate with 'a movable armature, the front contact and the armature together constituting a short circuiting network for a loudspeaker, and the back contact andthe armature being utilized forthe purpose of controlling the energization of a light-source.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and together with additional objects and advantages thereof, will best be understood from the following description of a specic `embodiment when read in connection with the accompanying drawing.

Thefsingle figure of the drawing is a schematic PATENT OFFICE.

IVING SYSTEM CamdenQN. Jay, assignor, to Radio'Corporation of N. Y., a corporation of' 1930, SeriaLNo.. 476,312

circuit diagram of a complete radio receiver of the super-heterodyne type including a preferred embodiment of my invention. Y

- Referring specically'to'the drawing, a radio receiver ofthe super-heterodyne type comprises a blocking tube I; a firstV detector tube 3, an oscillator tube 5, apluralityof intermediate frequency amplifier tubes 1 andi); a'second detector tube I-I. and a plurality of power-amplifier tubes I3` ar.- ranged in push-pull` relation. In addition, the specific receiver illustrated' kincludes a volume control tube l5 and-a rectifier tube I1 across-the output terminals of which is connected a resistor or potentiometer I9 from which a pluralityof leads 2 I, 2-3, 25, 2-1, 29, 37|l and 33extend forthe purpose of supplyingiplate and; bias potentials to-l all of` the thermionic tubes inI the system.

The windingv of Va relaydevice 35 is included in the output circuit of the intermediate frequency amplier tube 9, the said device being provided with a: movable armature 31, a front contact 39 and a back contactV 4I'.. v

The front contactgfand the movable armature 31 are'connected across the voice coil of'aloud speaker AS'that-,is supplied with audio frequency current'froml thefsecondary winding of anV audio frequency transformer the primary winding of which -constitutes the output circuit oi" the power-amplifier tubes I3.

The back contact 41' and the-movable armature 31 are Vserially connected with a light source 46- to the terminals of a secondary winding 4:1 associated'withy apower transformer 49 which supplies filament and platepotential for the rectifier. Fromy an inspection of the Vdrawingf it will be noted that the plate of the intermediate frequency ampiier tube 9 is supplied with potential over two parallel circuits, one circuit including the winding of the relay device 35, and the other circuit including the. movable contact of a potentiometer 5|- connectedV across aportion of the output resistor I9 associated with. the rectiiier. Y v

The purpose of. the parallel` plate-supply circuits will hereinafter be explained in detail.

In order that the operation of my improved radio receiving system may be thoroughly understood, it shouldA first be assumed that no signalis being received. In such event no current ows in a plurality of resistors 53 and 55 that are serially. included. in the output circuit ofthe volume control tube l5 since the grid thereof, normally, is-biaSed. to substantially the cut-off point by reason of a connection 51 extending therefrom to a point on the resistor i9 adjacent to the negative end thereof.

Inasmuch as the grids of the amplifying tubes I, 1 and 9 are connected to the resistors 53 and which, in turn, are connected to a point on the rectifier output-resistor I9 that is more negative than the points to which the leads 25 and 21 thereto from the cathodes of the several are connected, the said grids are normally biased, during the no-signal condition of the system, to a potential such that a predetermined amount of plate current flows therein.

By adjusting the contact element of the potentiometer 5| connected around the upper end of the resistor the current flow in thewinding of the relay during the no-signal condition, may be so fixed that the armature thereof is normally maintained against the front contact, thus establishing a short circuit around the voice coil of the loud speaker and preventing the tuning operation from being accompanied by a background of noise.

As soon, however, as the system is tuned to an incoming signal the said signal is impressed upon the grid of the volume control tube causing an increase in the output current Ytherefrom and a consequent application of a more negative potential to the grid of the amplifying tube 9 connected to the resistor 53. r

The more negative potential applied to the amplifier grid causes a decrease in the plate current therefrom and a partial de-energizing of the relay winding. The defenergization of the relay winding permits the armature to fall out against the back contact Y4| thus removing the short circuit previously established around the voice coil of vthe loud speaker and completing a circuit whereby the light source is supplied with energizing potential from the secondary winding 41. If the tuning of the system is not exact no signal is impressed upon the grid of the volume control tube and the relay device remains energized, thus giving an indication ofthe tuning of the system to exact resonance with the frequency of the incoming signal.

I have piu'posely refrained from indicating the light source as being disposed in any particular position. It may, without departing from the spirit of my invention, be included in a remote control device, disposed behind the dial of a radio receiver, or so, mounted behind the panel of the receiver that it illuminates asmall Window inserted therein.

Although I have illustrated and described a specific embodiment of my invention, many modificationsthereof Will be apparent to those skilled in the art to which it pertains. My invention, therefore, is not to be limited except insofar as is necessitated bythe prior art or by the spirit of the appended claims.

I claim as my invention.

1. In a signal receiving system, the combination of tuning means for the selection of signals, means for translating received signals into audible sounds, visual indicating means including a lamp, means for normally maintaining said sound translating means and said lamp de-energized, means responsive to selected signals for permitting energization of said sound translating means and said lamp, means for adjusting the energization permitting means to be responsive only to signals of predetermined minimum strength, whereby the lamp provides a visual indication of the operation of the tuning means in selecting a.

signal to be received, and the sound translating tinuity of the power circuit, signal responsive automatic volume control means for causing diminution of space current in the amplifier tube and consequent de-energization of the relay during reception of a desired signal, and means for completing the power circuit upon de-energization of the relay whereby the illumination given by the light source indicates exact tuning of the receiver.

3. In a signal receiving system an amplifier tube having anlinput circuit and an output circuit, a volume control tube having an input circuit and an output circuit, means for impressing potentials proportional to incoming signals upon the said input circuits, means for deriving unidirectional potentials from the output circuit of the volume-control tube, connections for applying said unidirectional potentials to the input circuit of the amplifier tube to control the gain therein, the' said connections being such that the gain varies inversely with the amplitude of the signals, a loudspeaker, a light source, a relay winding included in the output circuit of the amplifier tube, said relay being provided with front contacts interposed in a circuit which controls the energization of the loudspeaker and back contacts interposed in a circuit including the light source and potential-supply means therefor, and means for so adjusting the space current traversing the relay winding that the front contacts are maintained closed during the operation of tuning the system and are permitted to open when a desired signal is impressed upon the input circuit of the volume control tube to cause the latter to reduce the space current in theamplier tube.

4. In` asignal-receiving system, an amplifier tube, means for applying a negative bias to the input circuit of said tube inversely proportional to the amplitude of an incoming signal, a light source, a loudspeaker, and means responsive to changes-in the output current from said amplifier tube for controlling the energization of the light source and for rendering said loudspeaker ineffective.

5. In a signal-receiving system, an amplifier tube, Vmeans for applying a negative bias to the input circuit of said Vtube inversely proportional to the amplitude of an incoming signal, a light source, a, loudspeaker, and means responsive to changes in the output current from said amplifier tube for so controlling the energization of the light source and the loudspeaker, that the light source and loudspeaker are energized only upon the tuning-in of a sustained signal of predetermined amplitude.`

6.1In a signal-receiving system, an amplifier tube, means for applying a negative bias to the input circuit of said tube inversely proportional to the amplitude of an incoming signal, a light source, a loudspeaker, and means responsive to changes inthe output current from said amplifier tube for controlling the energization of the light source and the loudspeaker, the output current responsive means being constituted by a relay, the winding ofV which is included in the output circuit of the controlled amplifier tube to be energized by the plate current therein.A

7. In a signabreceiving system, an amplier tube, means for applying a negative bias to the input circuit of said tube inversely proportional to the amplitude of an incoming signal, a light source, a loudspeaker, and means responsive to changes in the output current from said amplier tube for controlling the energization of the light source and .the loudspeaker, the output current responsive means being constituted by a relay, the winding of which is included in the output circuit of the controlled amplifier tube Vto be energized by the space current therein and means for manually controlling the amplitude of the current transversing said winding.

8. In a signal receiving system, an amplifier tube, a relay device connected to the output circuit of said tube, a light source, a power circuit for the light source, means responsive at all times to energization of said relay for rendering said power circuit ineffective to energize said light source, automatic volume control means for causing suiicient space current flow in said amplifier tube to energize said relay and thereby de-energize said light source in response to tuning said receiving system away from an incoming signal and for causing diminution of space current in said amplifier tube to de-energize said relay in response to tuning said receiving system to an incoming signal, said rst means also rendering said Vpower circuit effective to energize said light source in response to de-energization of said relay whereby the illumination given by said light source indicates exact tuning ofthe receiver.

WINFIELD RUDOLPH KOCH. 

